1281798777825 has 72 divisors (see below), whose sum is σ = 2353235930136. Its totient is φ = 666556416000.

The previous prime is 1281798777793. The next prime is 1281798777839. The reversal of 1281798777825 is 5287778971821.

It can be written as a sum of positive squares in 12 ways, for example, as 135605853009 + 1146192924816 = 368247^2 + 1070604^2 .

It is not a de Polignac number, because 1281798777825 - 2⁵ = 1281798777793 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 15835857 + ... + 15916593.

It is an arithmetic number, because the mean of its divisors is an integer number (32683832363).

Almost surely, 2^{1281798777825} is an apocalyptic number.

1281798777825 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1281798777825 is a deficient number, since it is larger than the sum of its proper divisors (1071437152311).

1281798777825 is a wasteful number, since it uses less digits than its factorization.

1281798777825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82515 (or 82507 counting only the distinct ones).

The product of its digits is 221276160, while the sum is 72.

The spelling of 1281798777825 in words is "one trillion, two hundred eighty-one billion, seven hundred ninety-eight million, seven hundred seventy-seven thousand, eight hundred twenty-five".